Static random access memory (SRAM) is a type of volatile semiconductor memory that stores data bits using bi-stable circuitry. Bi-stable circuitry will maintain the integrity of a stored bit without refreshing. A single SRAM cell is referred to as a bit cell because the single SRAM cell stores one bit of information, represented by a logic state of two cross coupled inverters. Memory arrays include multiple bit cells arranged in rows and columns. In some approaches, each bit cell in a memory array includes a connection to a power supply voltage and a connection to a reference voltage. Logic signals on bit lines control reading from and writing to a bit cell, with a word line controlling connections of the bit lines to the cross-coupled inverters through pass gates. When the pass gates are in a non-conductive state, the bit cell floats.
Scaling of semiconductor devices, e.g., a metal-oxide semiconductor field-effect transistor (MOSFET), has enabled continued improvement in speed, performance, density, and cost per unit function of integrated circuits over the past few decades. The reduced size of MOSFETs results in changes to carrier mobility, which in turn impacts a drive current through the MOSFET.